1. Technical Field
The present disclosure generally relates to wellbore servicing. More specifically, this disclosure relates to materials for treating lost circulation.
2. Background
Natural resources such as gas, oil, and water residing in a subterranean formation can be recovered by drilling wells into the formation. Well drilling involves drilling a wellbore down to the formation while circulating a drilling fluid or mud through the wellbore. Various types of drilling fluids, also known as drill-in fluids when used in the productive interval, have been used in well drilling, such as water-based fluids, mineral oil-based fluids, and synthetic oil-based fluids.
The subterranean formation is then usually isolated from other formations using a technique known as well cementing. Subsequently, oil or gas residing in the subterranean formation may be recovered by driving the fluid into the well using, for example, a pressure gradient that exists between the formation and the wellbore, the force of gravity, displacement of the fluid using a pump or the force of another fluid injected into the well or an adjacent well. The production of the fluid in the formation may be increased by hydraulically fracturing the formation. That is, a viscous fracturing fluid may pumped down the wellbore to the formation at a rate and a pressure sufficient to form fractures that extend into the formation, providing additional pathways through which the oil or gas can flow to the well. Unfortunately, water rather than oil or gas may eventually be produced by the formation through the fractures therein. To provide for the production of more oil or gas, a fracturing fluid may again be pumped into the formation to form additional fractures therein. However, the previously used fractures first must be plugged to prevent the loss of the fracturing fluid into the formation via those fractures.
In addition to the fracturing fluid, other fluids used in servicing a wellbore may also be lost to the subterranean formation while circulating the fluids in the wellbore or otherwise placing fluids in the wellbore. In particular, the fluids may enter and be “lost” to the subterranean formation via depleted zones, zones of relatively low pressure, lost circulation zones having naturally occurring fractures, weak zones having fracture gradients exceeded by the hydrostatic pressure of the drilling fluid, and so forth. As a result, the service provided by such fluid is more difficult to achieve. For example, a drilling fluid may be lost to the formation, resulting in the circulation of the fluid in the wellbore being terminated and/or too low to allow for further drilling of the wellbore. Such conditions may be referred to as partial or complete loss of circulation or lost circulation.
Conventional methods of treating lost circulation take into consideration many aspects related to the type of wellbore servicing operation being carried out. One such aspect involves removal of the materials used to treat lost circulation subsequent to drilling the wellbore. For example, some materials used to treat lost circulation are subsequently removed by degrading the materials with acid. In such instances the wellbore servicing operation faces challenges associated with both the handling of large volumes of acid in addition to the potential for formation damage.
Accordingly, an ongoing need exists for compositions and methods of treating lost circulation.